This invention is in the field of gas storage technology. This invention relates generally to materials and methods for improved adsorption of methane and other gases on porous adsorbents.
Unlike that of liquids, which typically possess a relatively high density, the density of gases is relatively low. This provides a challenge for high-density storage of chemical species that possess a condensation temperature or critical temperature below common environmental temperatures.
Methods are available, however, for storage of gases at densities higher than at standard pressure and temperature conditions. For example, gases can be stored in a compressed state. Compressed gases, however, still do not possess a density as high as liquids and typically require heavy and bulky storage tanks.
Additionally, some gases can be compressed into a liquid state at standard temperature conditions. For example, propane and propane/butane mixtures are commonly compressed to a liquid state for storage and transport. Such a technique for liquefaction cannot generally be used for gases such as hydrogen and methane, however, because they have critical temperatures well below common environmental temperatures.
To overcome this limitation, gases are sometimes cooled to low or cryogenic temperatures to achieve liquefaction. For example, natural gas is commonly cooled to a liquid state for storage and transport, though this typically requires considerable insulation and cooling systems to maintain the cold temperatures for long periods of time.
Gas storage in compressed systems can also be enhanced by adsorption of the gas onto the surface of an adsorbent material. For example, Himeno et al., Journal of Chemical and Engineering Data, 50:2, 369-376 (2005), discloses the use of various microporous activated carbons for adsorption of gases such as methane and carbon dioxide.
More recently, U.S. Patent Application Publication US 2011/0052486 discloses microporous carbon materials for use in hydrogen and methane storage applications. Additionally, Stadie et al., Langmuir, 28, 10057 (2012) discloses zeolite-templated carbon materials for use in hydrogen storage applications. Also, Nishihara et al., Advanced Materials, 24, 4473-4498 (2012), discloses a variety of templated nanoporous carbon materials for use in hydrogen storage applications.
In Scientific Reports 3, 1935 (2013) and Scientific Reports 3, 2420 (2013), Xia et al. and Li et al. respectively disclose methods for forming porous carbon materials from metal-organic gel templates for hydrogen storage and carbonized porous aromatic frameworks for storage of methane, hydrogen and carbon dioxide.
There remains, however, a need for enhanced gas storage materials and methods.